The present invention relates to a charged-particle beam exposure apparatus and a control method therefor and, more particularly, to a charged-particle beam exposure apparatus for drawing a pattern on a substrate with a charged particle beam, a control method therefor, a device manufacturing method using the charged-particle beam exposure apparatus controlled by the control method, an exposure system having the charged-particle beam exposure apparatus, and a control method therefor.
As charged-particle beam exposure apparatuses, there are, e.g., an electron beam exposure apparatus and ion beam exposure apparatus. The charged-particle beam exposure apparatus is used to draw a desired pattern on a substrate (e.g., a wafer or glass plate) for forming a semiconductor integrated circuit, a mask or reticle for manufacturing a semiconductor integrated circuit, or a display apparatus such as an LCD.
In general, charged-particle beam exposure divides a pattern to be exposed into a plurality of element exposure fields, and draws a pattern by raster scan using charged particles within each element exposure field. The size of the element exposure field is set as large as possible in order to increase the throughput of exposure processing as far as the influence of aberration by the electron optical system of this apparatus is weak.
When a pattern is to be formed on a wafer using a charged particle beam, the apparatus suffers a so-called proximity effect that charged particles irradiating the wafer scatter in a resist and substrate, failing to obtain a designed pattern. Under the influence of the proximity effect, a pattern becomes thinner than a design value on a thin pattern (e.g., an isolated thin pattern) having a low drawing density, and patterns which should be separated are connected to each other on a pattern (e.g., a pattern sandwiched between large patterns) having a high drawing density.
To prevent this, the charged-particle beam exposure apparatus adopts a method of drawing a pattern in each element exposure field while controlling the dosage (dose) so as to exclude the influence of the above-described proximity effect in accordance with a drawing pattern.
According to an example of this method, a pattern is drawn while the dosage per dot is controlled. This method, however, performs dosage setting operation every time one dot is drawn, and the throughput of exposure processing is not practical.
To solve this problem, as shown in FIG. 9, an element exposure field is subdivided into smaller partial fields to set a dose for each partial field. For example, as shown in FIG. 9, an element exposure field is divided into four partial fields 91 to 94, and doses (Dose(1), Dose(2), Dose(3), and Dose(4)) are set for the respective partial fields.
Also in this case, however, the throughput is low. As is apparent from FIG. 9, one scan line lies across two partial fields, so that the dose must be changed (from Dose(1) to Dose(2)) during the first scan, and returned (from Dose(2) to Dose(1)) again at the start of the second scan.
In this manner, even if a dose is to be set for each partial field prepared by subdividing an element exposure field, the dose must be frequently changed, a time required for data transfer to a blanker control circuit for switching the dosage and data setting (set ring) increases, and the throughput of exposure processing greatly decreases.
The present invention has been made to overcome the conventional drawbacks, and had as its object to provide a charged-particle beam exposure apparatus capable of more effectively excluding an adverse effect caused by the proximity effect while maintaining the throughput of exposure processing, and a control method therefor.
A charged-particle beam exposure apparatus according to one aspect of the present invention for achieving the above object comprises the following arrangement.
That is, a charged-particle beam exposure apparatus for dividing each element exposure field having a size falling within a range where aberration by an electron optical system is suppressed to not more than a predetermined amount into a plurality of partial fields, and drawing a pattern on a substrate with a charged particle beam on the basis of exposure information in which charged-particle beam dosages for the plurality of partial fields are set comprises
scan/exposure means for continuously scanning and exposing an entire corresponding partial field with the dosage contained in the exposure information, thereby drawing a pattern, and
execution means for sequentially executing scan/exposure by the scan/exposure means for all partial fields in the element exposure field, thereby drawing a pattern in the element exposure field.
An exposure system according to another aspect of the present invention for achieving the above object comprises the following arrangement.
That is, an exposure system having a charged-particle beam exposure apparatus for drawing a pattern on a substrate with a charged particle beam on the basis of exposure information comprises
determination means for dividing an element exposure field having a size falling within a range where aberration by an electron optical system is suppressed to not more than a predetermined amount into a plurality of partial fields, and determining charged-particle beam dosages for the plurality of partial fields on the basis of a drawing pattern,
providing means for providing the charged-particle beam exposure apparatus with exposure information containing the dosages determined by the determination means and the drawing pattern for the respective partial fields,
scan/exposure means for continuously scanning and exposing an entire corresponding partial field with the dosage contained in the exposure information, thereby drawing a pattern, and
execution means for sequentially executing scan/exposure by the scan/exposure means for all partial fields included in the element exposure field, thereby drawing a pattern in the element exposure field.
A control method for a charged-particle beam exposure apparatus according to still another aspect of the present invention for achieving the above object comprises the following steps.
That is, a control method for a charged-particle beam exposure apparatus for dividing each element exposure field having a size falling within a range where aberration by an electron optical system is suppressed to not more than a predetermined amount into a plurality of partial fields, and drawing a pattern on a substrate with a charged particle beam on the basis of exposure information in which charged-particle beam dosages for the plurality of partial fields are set comprises
the scan/exposure step of continuously scanning and exposing an entire corresponding partial field with the dosage contained in the exposure information, thereby drawing a pattern, and
the execution step of sequentially executing scan/exposure in the scan/exposure step for all partial fields in the element exposure field, thereby drawing a pattern in the element exposure field.
A control method for a charged-particle beam exposure apparatus according to still another aspect of the present invention for achieving the above object comprises the following steps.
That is, a control method for an exposure system having a charged-particle beam exposure apparatus for drawing a pattern on a substrate with a charged particle beam on the basis of exposure information comprises
the determination step of dividing an element exposure field having a size falling within a range where aberration by an electron optical system is suppressed to not more than a predetermined amount into a plurality of partial fields, and determining charged-particle beam dosages for the plurality of partial fields on the basis of a drawing pattern,
the providing step of providing the charged-particle beam exposure apparatus with exposure information containing the dosages determined in the determination step and the drawing pattern for the respective partial fields,
the scan/exposure step of continuously scanning and exposing an entire corresponding partial field with the dosage contained in the exposure information, thereby drawing a pattern, and
the execution step of sequentially executing scan/exposure in the scan/exposure step for all partial fields included in the element exposure field, thereby drawing a pattern in the element exposure field.
The present invention for achieving the above object provides a device manufacturing method including the step of drawing a pattern on a substrate while controlling a charged-particle beam exposure apparatus by the above-described control method.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.